Abstract: Strontium tetraborate is used as an optical coating material for optical components utilized in semiconductor inspection and metrology systems to take advantage of its high refractive indices, high optical damage threshold and high microhardness in comparison to conventional optical materials. At least one layer of strontium tetraborate is formed on the light receiving surface of an optical component's substrate such that its thickness serves to increase or decrease the reflectance of the optical component. One or multiple additional coating layers may be placed on top of or below the strontium tetraborate layer, with the additional coating layers consisting of conventional optical materials. The thicknesses of the additional layers may be selected to achieve a desired reflectance of the optical component at specific wavelengths. The coated optical component is used in an illumination source or optical system utilized in a semiconductor inspection system, a metrology system or a lithography system.

Abstract: Strontium tetraborate can be used as an optical material. Strontium tetraborate exhibits high refractive indices, high optical damage threshold, and high microhardness. The transmission window of strontium tetraborate covers a very broad range of wavelengths, from 130 nm to 3200 nm, making the material particularly useful at VUV wavelengths. An optical component made of strontium tetraborate can be incorporated in an optical system, such as a semiconductor inspection system, a metrology system, or a lithography system. These optical components may include mirrors, lenses, lens arrays, prisms, beam splitters, windows, lamp cells or Brewster-angle optics.

Abstract: A broadband ultraviolet illumination source for a characterization system is disclosed. The broadband ultraviolet illumination source includes an enclosure having one or more walls, the enclosure configured to contain a gas, and a plasma discharge device based on a graphene-dielectric-semiconductor (GOS) planar-type structure. The GOS structure includes a silicon substrate having a top surface, a dielectric layer disposed on the top surface of the silicon substrate, and at least one layer of graphene disposed on a top surface of the dielectric layer. A metal contact may be formed on the top surface of the graphene layer. The GOS structure has several advantages for use in an illumination source, such as low operating voltage (below 50 V), planar surface electron emission, and compatibility with standard semiconductor processes. The broadband ultraviolet illumination source further includes electrodes placed inside the enclosure or magnets placed outside the enclosure to increase the current density.

Abstract: Strontium tetraborate is used as an optical coating material for optical components utilized in semiconductor inspection and metrology systems to take advantage of its high refractive indices, high optical damage threshold and high microhardness in comparison to conventional optical materials. At least one layer of strontium tetraborate is formed on the light receiving surface of an optical component's substrate such that its thickness serves to increase or decrease the reflectance of the optical component. One or multiple additional coating layers may be placed on top of or below the strontium tetraborate layer, with the additional coating layers consisting of conventional optical materials. The thicknesses of the additional layers may be selected to achieve a desired reflectance of the optical component at specific wavelengths. The coated optical component is used in an illumination source or optical system utilized in a semiconductor inspection system, a metrology system or a lithography system.

Abstract: A multiple-column-per-channel image CCD sensor utilizes a multiple-column-per-channel readout circuit including connected transfer gates that alternately transfer pixel data (charges) from a group of adjacent pixel columns to a shared output circuit at high speed with low noise. Charges transferred along the adjacent pixel columns at a line clock rate are alternately passed by the transfer gates to a summing gate that is operated at multiple times the line clock rate to pass the image charges to the shared output circuit. A symmetrical fork-shaped diffusion is utilized in one embodiment to merge the image charges from the group of related pixel columns. A method of driving the multiple-column-per-channel CCD sensor with line clock synchronization is also described. A method of inspecting a sample using the multiple-column-per-channel CCD sensor is also described.

Abstract: A dual-column-parallel image CCD sensor utilizes a dual-column-parallel readout circuit including two pairs of cross-connected transfer gates to alternately transfer pixel data (charges) from a pair of adjacent pixel columns to a shared output circuit at high speed with low noise. Charges transferred along the two adjacent pixel columns at a line clock rate are alternately passed by the transfer gates to a summing gate that is operated at twice the line clock rate to pass the image charges to the shared output circuit. A symmetrical Y-shaped diffusion is utilized in one embodiment to merge the image charges from the two pixel columns. A method of driving the dual-column-parallel CCD sensor with line clock synchronization is also described. A method of inspecting a sample using the dual-column-parallel CCD sensor is also described.

Abstract: A photocathode utilizes an field emitter array (FEA) integrally formed on a silicon substrate to enhance photoelectron emissions, and a thin boron layer disposed directly on the output surface of the FEA to prevent oxidation. The field emitters are formed by protrusions having various shapes (e.g., pyramids or rounded whiskers) disposed in a two-dimensional periodic pattern, and may be configured to operate in a reverse bias mode. An optional gate layer is provided to control emission currents. An optional second boron layer is formed on the illuminated (top) surface, and an optional anti-reflective material layer is formed on the second boron layer. An optional external potential is generated between the opposing illuminated and output surfaces. An optional combination of n-type silicon field emitter and p-i-n photodiode film is formed by a special doping scheme and by applying an external potential. The photocathode forms part of sensor and inspection systems.

Abstract: An image sensor utilizes a pure boron layer and a second epitaxial layer having a p-type dopant concentration gradient to enhance sensing DUV, VUV or EUV radiation. Sensing (circuit) elements and associated metal interconnects are fabricated on an upper surface of a first epitaxial layer, then the second epitaxial layer is formed on a lower surface of the first epitaxial layer, and then a pure boron layer is formed on the second epitaxial layer. The p-type dopant concentration gradient is generated by systematically increasing a concentration of p-type dopant in the gas used during deposition/growth of the second epitaxial layer such that a lowest p-type dopant concentration of the second epitaxial layer occurs immediately adjacent to the interface with the first epitaxial layer, and such that a highest p-type dopant concentration of the second epitaxial layer occurs immediately adjacent to the interface with pure boron layer.

Abstract: An electron gun for an electron microscope or similar device includes a field emitter cathode having a field emitter protrusion extending from the output surface of a monocrystalline silicon substrate, and electrodes configured to enhance the emission of electrons from a tip portion of the field emitter protrusion to generate a primary electron beam. A thin, contiguous SiC layer is disposed directly on at least the tip portion of the field emitter protrusion using a process that minimizes oxidation and defects in the SiC layer. Optional gate layers may be placed at, slightly lower than or slightly higher than the height of the field emitter tip portion to achieve high emission current and fast and accurate control of the primary emission beam. The field emitter can be p-type doped and configured to operate in a reverse bias mode, or the field emitter can be n-type doped.

Abstract: An electron source is formed on a silicon substrate having opposing first and second surfaces. At least one field emitter is prepared on the second surface of the silicon substrate to enhance the emission of electrons. To prevent oxidation of the silicon, a thin, contiguous boron layer is disposed directly on the output surface of the field emitter using a process that minimizes oxidation and defects. The field emitter can take various shapes such as pyramids and rounded whiskers. One or several optional gate layers may be placed at or slightly lower than the height of the field emitter tip in order to achieve fast and accurate control of the emission current and high emission currents. The field emitter can be p-type doped and configured to operate in a reverse bias mode or the field emitter can be n-type doped.

Abstract: An image sensor for electrons or short-wavelength light includes a semiconductor membrane, circuit elements formed on one surface of the semiconductor membrane, and a pure boron layer on the other surface of the semiconductor membrane. The circuit elements are connected by metal interconnects comprising a refractory metal. An anti-reflection or protective layer may be formed on top of the pure boron layer. This image sensor has high efficiency and good stability even under continuous use at high flux for multiple years. The image sensor may be fabricated using CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) technology. The image sensor may be a two-dimensional area sensor, or a one-dimensional array sensor.

Abstract: A scanning electron microscope incorporates a multi-pixel solid-state electron detector. The multi-pixel solid-state detector may detect back-scattered and/or secondary electrons. The multi-pixel solid-state detector may incorporate analog-to-digital converters and other circuits. The multi-pixel solid state detector may be capable of approximately determining the energy of incident electrons and/or may contain circuits for processing or analyzing the electron signals. The multi-pixel solid state detector is suitable for high-speed operation such as at a speed of about 100 MHz or higher. The scanning electron microscope may be used for reviewing, inspecting or measuring a sample such as unpatterned semiconductor wafer, a patterned semiconductor wafer, a reticle or a photomask. A method of reviewing or inspecting a sample is also described.

Abstract: An inspection system and methods in which analog image data values (charges) captured by an image sensor are binned (combined) before or while being transmitted as output signals on the image sensor's output sensing nodes (floating diffusions), and in which an ADC is controlled to sequentially generate multiple corresponding digital image data values between each reset of the output sensing nodes. According to an output binning method, the image sensor is driven to sequentially transfer multiple charges onto the output sensing nodes between each reset, and the ADC is controlled to convert the incrementally increasing output signal after each charge is transferred onto the output sensing node. According to a multi-sampling method, multiple charges are vertically or horizontally binned (summed/combined) before being transferred onto the output sensing node, and the ADC samples each corresponding output signal multiple times. The output binning and multi-sampling methods may be combined.

Abstract: An inspection system including an optical system (optics) to direct light from an illumination source to a sample, and to direct light reflected/scattered from the sample to one or more image sensors. At least one image sensor of the system is formed on a semiconductor membrane including an epitaxial layer having opposing surfaces, with circuit elements formed on one surface of the epitaxial layer, and a pure boron layer and a doped layer on the other surface of the epitaxial layer. The image sensor may be fabricated using CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) technology. The image sensor may be a two-dimensional area sensor, or a one-dimensional array sensor. The image sensor can be included in an electron-bombarded image sensor and/or in an inspection system.

Abstract: A multiple-column-per-channel image CCD sensor utilizes a multiple-column-per-channel readout circuit including connected transfer gates that alternately transfer pixel data (charges) from a group of adjacent pixel columns to a shared output circuit at high speed with low noise. Charges transferred along the adjacent pixel columns at a line clock rate are alternately passed by the transfer gates to a summing gate that is operated at multiple times the line clock rate to pass the image charges to the shared output circuit. A symmetrical fork-shaped diffusion is utilized in one embodiment to merge the image charges from the group of related pixel columns. A method of driving the multiple-column-per-channel CCD sensor with line clock synchronization is also described. A method of inspecting a sample using the multiple-column-per-channel CCD sensor is also described.

Abstract: An inspection system/method in which first optics direct continuous wave (CW) light at 181-185 nm to an inspected article, and second optics redirect image information affected by the article to detectors. A laser assembly generates the CW light by generating fourth harmonic light from first fundamental CW light having a first wavelength between 1 and 1.1 ?m, generating fifth harmonic light by mixing the fourth harmonic light with the first fundamental CW light, and mixing the fifth harmonic light with second light having a second wavelength between 1.26 and 1.82 ?m. An external cavity mixes the first light and the fourth harmonic light using a first nonlinear crystal. The CW light is generated using a second cavity that passes circulated second fundamental or signal CW light through a second nonlinear crystal, and directing the fifth harmonic light through the second nonlinear crystal.

Abstract: A system for measuring an overlay error of a sample is disclosed. The system may include a broadband illumination source configured to emit broadband illumination. The system may also include one or more optical elements configured to direct the broadband illumination to a target disposed on the sample, wherein the one or more optical elements are configured to collect illumination from the target and direct it to a spectrometer, wherein the spectrometer is configured to disperse multiple wavelengths of the illumination collected from the sample to multiple elements of a sensor to generate a plurality of signals. The system may also include a controller configured to calculate an overlay error between a first structure and a second structure of the target by comparing the plurality of signals with a plurality of calculated signals.

Abstract: A dual-column-parallel image CCD sensor utilizes a dual-column-parallel readout circuit including two pairs of cross-connected transfer gates to alternately transfer pixel data (charges) from a pair of adjacent pixel columns to a shared output circuit at high speed with low noise. Charges transferred along the two adjacent pixel columns at a line clock rate are alternately passed by the transfer gates to a summing gate that is operated at twice the line clock rate to pass the image charges to the shared output circuit. A symmetrical Y-shaped diffusion is utilized in one embodiment to merge the image charges from the two pixel columns. A method of driving the dual-column-parallel CCD sensor with line clock synchronization is also described. A method of inspecting a sample using the dual-column-parallel CCD sensor is also described.

Abstract: A laser system includes a nonlinear optical (NLO) crystal, wherein the NLO crystal is annealed within a selected temperature range. The NLO crystal is passivated with at least one of hydrogen, deuterium, a hydrogen-containing compound or a deuterium-containing compound to a selected passivation level. The system further includes at least one light source, wherein at least one light source is configured to generate light of a selected wavelength and at least one light source is configured to transmit light through the NLO crystal. The system further includes a crystal housing unit configured to house the NLO crystal.

Abstract: A dual-column-parallel image CCD sensor utilizes a dual-column-parallel readout circuit including two pairs of cross-connected transfer gates to alternately transfer pixel data (charges) from a pair of adjacent pixel columns to a shared output circuit at high speed with low noise. Charges transferred along the two adjacent pixel columns at a line clock rate are alternately passed by the transfer gates to a summing gate that is operated at twice the line clock rate to pass the image charges to the shared output circuit. A symmetrical Y-shaped diffusion is utilized in one embodiment to merge the image charges from the two pixel columns. A method of driving the dual-column-parallel CCD sensor with line clock synchronization is also described. A method of inspecting a sample using the dual-column-parallel CCD sensor is also described.